


Never Expected That

by Notaname



Category: Fire Emblem Series, Fire Emblem: If | Fire Emblem: Fates
Genre: Accidental Voyeurism, After a few months this got filled, F/M, Masturbation, One-Sided Attraction, Prompt Fill, Step-Sibling Incest
Language: English
Status: Completed
Published: 2015-12-12
Updated: 2015-12-12
Packaged: 2018-05-06 06:12:02
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,927
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5406011
Author URL: https://archiveofourown.org/users/Notaname/pseuds/Notaname
Summary: <blockquote class="userstuff">
              <p>Leo had made up his mind. He was finally going to propose to Corrin. </p>
<p>What Leo hadn't been accounting for was his older brother proposing first; or Corrin saying yes. As hard as that was, he really didn't need to listen in on them having sex. His legs just didn't seem to want to move though.</p>
            </blockquote>





	Never Expected That

**Author's Note:**

> Finally decided to fill this for /feg/. Also using the opportunity to try to get used to the English names.

Tapping his finger impatiently, Leo spared a glance out the window. He had been waiting all day for Corrin to ride through the gates. She had been out running, some sort of errand, Leo was sure he should have been paying attention during the war meeting where the details had been discussed. Normally he would have been paying more attention, or even speaking his own thoughts on the situation. Ever since his talk with Xander a while ago he had been speaking out more often, not afraid to go against something he thought was wrong. He hadn’t been speaking up for the last few weeks. Not from lack of wanting to, no, he had just been very distracted. A slight flush spread across his face as his thoughts drifted yet again to the source of his distractions. Corrin. It seemed like all he did these days was think about his sister, no she was his adopted sister. ‘Adopted!’ He thought giddily.

It had been a hard shock for all of them when they had found that little fact out. After the shock had worn off though things had changed. Leo would be the first to admit, to himself anyway, that he had a crush on his sister. It had always been safely locked behind the wall of ‘They were related, you can’t have her.’ Leo had always thought that he would get over it eventually, move past it like he had with Camilla. That notion had been ripped to shreds though with the fateful announcement that Corrin had been kidnapped from her real family. 

The floodgates had burst open, now every hidden little fantasy, every half conjured thought, every dream he had ever had of her, and more barraged him at every moment in the day. He could barely sit at the table with her without thinking what it would be like to run his fingers through her long hair, to kiss those perfect lips, to hold her hand, or feel the curve of her breasts in his hands, to push those beautiful milky thighs apart. Leon had never hated Camillas designing of all their outfits more than he had lately. Just looking at her, all the curves accentuated, the cravat around her neck leading down to her cleavage, the contrast of her visible panties against her pale skin. His life was a living nightmare now. 

What hadn’t helped him was the fact that Corrin was insisting on spending as much time as she could with all of them. She could be found with one of them at all times it seemed. If she wasn’t playing with Elise she was with gossiping with Camilla. At night Leo had found Corrin and Xander practicing their swordplay. He himself had been harassed for a day or so before giving in and teaching her magic. 

It was a new source of torment for him, he could barely focus on the words on the page, let alone teach her magic. She was just so close to him during those lessons. Sometimes their legs brushed against each other. Whenever that happened she would give a small giggle, maybe kick him in the shin, or give him that teasing smile of hers. Honestly, Leo was just happy she had never gotten into the habit of sneaking into his room at night like she had with Xander and Camilla. Apparently he kicked. She had told him that once when she was little before rushing over to Camilla’s side and begging to sleep in her bed that night.

A loud shout broke him from his thoughts and he whipped his head over to the window. The large gate was opening and Corrin was riding through, her long hair fluttering behind her like banner. He forced himself to swallow at the sight of her, swinging down from her horse and walking over to where Leo could see his older brother striding through the courtyard towards her. The two were soon wrapped in conversation as they headed out of his sight, most likely discussing how her mission went. Leo wanted to let her catch up with the rest of her family first before he confronted her. He knew Xander had wanted him to be down there when she got back for whatever reason. Leo had ignored that though in favor of building up his courage.

Taking a deep breath, Leo watched as for a moment longer trying to steady himself. Today was the day. He was going to put it all on the line. Reaching into his pocket normally clever fingers fumbling over the delicate ring within. It was both reassuring and frightening. If everything went how he thought it would go, how he hoped it would go, then Corrin and him would be spending the rest of their lives together. It had been a battle to come to terms with his feelings for his sister, even more to decide to ask for her hand. Since all he could do was focus on Corrin he had noticed all the little smiles she sent his way, how she had begged to be taught magic, all the time she was spending with him now. Leo was sure she returned his feelings. All he had to do is work up some courage and ask her. 

So caught up in his thoughts he missed the quiet squeak of the door opening. He never heard the two voices whispering to each other, or the soft footsteps as two people made their way to a darker corner in the library. What Leo did notice though was a familiar giggle breaking through the silence, he would know that sound anywhere. The blondes thoughts snapped back to the present and he turned his head towards the source of the sound. 

When had Corrin come into the library? Had she been looking for him? Leo’s usual frown pulled at his lips as he recognized Xanders deep voice answer whatever question Corrin had asked. What were the two of them doing here? Were they looking for him? Fumbling with the ring in his pocket before getting up from his hidden spot in the corner of the library. Leo didn’t really want to say what he had to say to Corrin in front of Xander, still, maybe they were looking for him? Maybe Corrin had found something while she was out? Quietly, the young Nohrian prince made his way over where he heard the two talking; straining his ears in an attempt to pick up what they were saying as he got closer. 

“I can’t believe you did it in front of everyone.” Corrin sounded flustered about something, though whatever it was must have been good, Leo could practically hear the smile on her face. Leo wasn’t able to catch the embarrassed deep mumble his brother gave. It was always funny how easily embarrassed their normally put together older brother could get. You could always tell when he started to mumble. It was something father used to yell at him endlessly for. Apparently Corrin didn’t understand either and she teased. “Speak up Xander. I didn’t quite catch that.”

Leo heard his brother sigh, he could practically see him running his hand nervously through his hair. “I said of course I did. Something that important I would do in front of everyone.” Leo could see the frown on Xander's face as he paused. “I do wish Leo was there though. I did send someone to find him.”

So that is Felicia had been doing up here. Of course the clumsy maid had knocked over a shelf to find him, but find him she had. She had been the one to tell him that Corrin would be coming home soon and that Xander wanted him to be there to greet her when she did. Which had sent him into his nervous fit of working up the courage to ask her again. It was going to be a make or break moment for him.

At this point he could see the two of them. Corrin leaning back against bookshelves her arms crossed under her breasts, pushing those pale mounds up just a bit. Xander’s back was to him so he couldn’t exactly tell what his brother was doing. Leo was about to reveal himself to the two of them, curious now about Xander's mysterious announcement. He didn’t though as Corrin started speaking again. “Well, I was certainly surprised. I mean… I can’t say I haven’t been hoping for it. Ever since we…” She trailed off here, an embarrassed flush spreading across her face. Oh she looked so beautiful face flushed like that, Leo hoped she blushed when he confessed to her. “Still, I said yes didn’t I?”

She said yes? To what? Leo was starting to feel a bit confused by this conversation. Ever responsible, his older brother provided him with an answer that almost had him falling to his knees. 

“Yes you did.” Xander voice was gentler than Leo ever remembered hearing from him. The blonde watched as Xander turned, leaned down slightly and pressed a loving kiss to Corrin’s lips. Kissing her how he imagined doing. Leo felt his heart drop as he watched Corrin eagerly push forward, returning the kiss. Just like he imagined she would kiss him back. 

Taking a steadying breath he willed his shaky legs to move, just a bit. Just to carry him a little further so he wouldn’t have to see his brother kiss the love of his life. Just so he wouldn’t have to watch said love of his life eagerly kiss his brother back. Leo managed to make it around the corner, leaning against the other side of the shelf as he sank down to the floor. He held back a soft sob as he heard a soft moan escape Corrins lips. His heart hurt so much. He had been so sure, so sure she returned his feelings. 

They must have stopped because Leon heard Corrin’s voice once more. He wished he could tune it out. That he didn’t hear the words coming from her mouth. Each more painful than the last. Sinking into his heart like a dagger with the next few. “I really am happy you proposed.” She had said yes to Xander. She was supposed to say yes to him. She would never say yes to him. “I don’t think I would have been able to keep things a secret for much longer anyway. “ Corrin admitted. 

‘Much longer?’ Leo’s thoughts echoed Corrin’s words. How long had this been going on? How long had he hopelessly been in a one sided relationship? The blonde bit back a sob that threatened to escape. Bringing his hand to his mouth he bit his palm, hoping the physical pain would help distract him from the pain in his heart. 

“To be honest I don’t think I could have either.” Xander hummed in agreement. “I think Camilla knew though.”

Corrin’s laugh was like a beautiful bell, the sound used to bring him peace, now it just hurt. “Why do you say that?”

“She kept making comments on how you never slept in her bed anymore. Or talking about a talented jeweler she knew that would have just the right ring for me.” Leo could hear the teasing amusement in Xanders voice as he talked. Camilla had known about them? How long had Corrin been sneaking into Xanders room to sleep? How long had it been since it had just been innocent sleeping?

“I love the ring you got me. I was so upset when I lost my bookmark. I was driving Flora and Felicia crazy looking for it, they practically tore my whole room apart in the search.” 

Bookmark? Leo recalled Corrin being upset about losing that a while ago. He had offered her one of his own many bookmarks only to be turned down. Corrin had quoted that one as being special to her. He vaguely remembered the thing, it had been a pressed flower ring, from the flowers they all used to weave into crowns and such. Suddenly he could picture it perfectly, the flowers from their childhood, one ring lovingly crafted after a treasured keepsake. Had it really been going on so long between the two of them? How had he not noticed?

“I am glad you like it little princess, but we really should be going.” 

“Hmm, I guess, I wonder where Leo is anyway? I thought for sure he would be in here.” 

They were looking for him? Why? To tell him that they were getting married? That his older brother, who he still very much loved was stealing the love of his life. The love of his life that had never felt the same way about him, that never would feel the same way about him. It hurt so much. If it was anyone else, anyone other than Xander he wouldn’t count himself out. The fact of the matter was that it did happen to be Xander, his big brother had beat him once again. Suddenly he was glad he had found out before they told him. He wasn’t sure what he would have done if he had been told in the hallway or in front of everyone. At least he had been spared the suffering of the actual proposal. Hearing ‘Yes’ from Corrin’s lips to a man who wasn’t himself would have been too horrible to bare. 

“I had thought he would be here as well.” Xander sighed and the bookshelf creaked a bit. He was probably leaning back against the shelves. “I am worried about him. He has been out of sorts lately. I was hoping a bit of good news would cheer him up.” 

Leo almost choked at Xanders words. ‘Why would he be happy? What about this could possibly make him happy?’ The sudden hot flash of anger was a new feeling for him. It also disappeared as quickly as it appeared. Of course they would think that, they didn’t know he had been falling in love with Corrin over the years. They didn’t know about the ring that felt like a brick in his pocket now. No one knew, he didn’t let them know. It was a little touching that Xander had even noticed, his older brother was always busy with something. That he had even noticed something was off, that he had wanted to do something about it even to cheer him up. If it wasn’t such a cruel twist of fate then it probably would have made Leo’s day. 

“You know, Leo really is the only person who spends hours and hours on end here…” Corrin trailed off a suggestive tone in her voice that Leo had never heard. Xander made an agreeable sound and Corrin pushed on. “I really missed you while I was away.” 

“You were only gone for a few days. I have been gone from the castle for much longer.”

“That’s true.” Kamui trailed off, dragging out the last bit.

“I can hear the ‘but’ in there.”

“Buuuuut, we were never seeing each other then. I missed your bed. I missed falling asleep next to you. I missed late night sword practices. I missed spending time with you. But you know what I missed most of all?” Corrin didn’t wait for a response before continuing on. “I missed having you inside of me.” She finished a teasing note in her voice.

For his part Leo couldn’t believe that had just come from his sister's mouth. It was slightly relieving to hear Xander choke a bit as well at her words, at least he wasn’t the only one suffering here. “Ah, Corrin, this is the library.” It was always so easy to forget that their confident older brother was the shyest one out of all of them. 

“I know, no one is here though.” She trailed off. Leo felt like now might be a good time to make his presence known. “Also, whenever I was studying magic with Leo in here, I had a hard time concentrating. My mind kept drifting off to what it would be like to make love to you in the library. I am amazed Leo never noticed I wasn’t always paying attention.” A nervous giggle escaped Corrin. Leo could hear the rustle of fabric and the shelves creak a bit as weight was added to them. Of course he had never noticed, he had been too busy daydreaming about bending her over the table and taking her for himself.

“He never noticed you kept daydreaming? I find that hard to believe.” Xander sounded amused as he teased Corrin. They were quiet for a moment, Leo couldn’t see them and wasn’t quite sure the reason for the pause. Xander broke the silence with a teasing query though. “In the library, really?” It sadly didn’t sound like his older brother was against the idea.

“Mmhmm.” Corrin made an affirming sound, there was a soft rustling of fabric and she said something that Leo couldn’t quite catch, though from the embarrassed chuckle Xander made it seemed like he had. Leo could make out her quiet “Please” though. The moment she breathed that, he knew that it was time to leave. Xander was, despite all outside appearance, a huge softy when it came to spoiling his siblings. He might deny them things in public, but Leo knew that he himself had received plenty of secret gifts from the older man. There was just no chance that he would say no. Not after finding all those rare books resting on his pillow late at night.

His suspicions were proved correct when he heard Xander sigh. “You really are spoiled. Alright, we need to keep it quick though.” His older brother had given in, and Leo should really be going now. There was a rustle of fabric, a shuffle of feet before a thud. The bookshelf Leo was against shuddered as, Corrin would be Leo’s bet, was shoved against it. He should really be leaving. From the soft gasps and the lack of words Leo was sure they were sharing a kiss, a kiss he desperately wished was giving to Corrin instead of his brother. Really, now was a perfect time to leave, his legs just didn’t seem to be working right at the moment. 

“Come on love.” Leo felt his heart clench in jealousy. “You can spoil me all you want tonight. We have to be quick now.” Corrin gasped. She must have done something, because Leo heard his brother grunt in response. 

‘I should really leave now.’ Leo desperately thought. Behind him he could hear Corrin’s pleasured gasps and it was just oh so easy to imagine it was him causing her to make that sweet music. It was so easy to imagine him pushing her against the shelves and kissing her senseless. The scenario was something he had toyed with a few times, a quiet but hurried love making session in the library. Well, it was happening, just, not how Leo had always imagined it. ‘I should really leave.’ Leo thought to himself as he reached down and absently stuck a hand into his pants, stroking his already half hard cock. Gods, what was wrong with him?

Leo’s little fantasy was shaken a bit at Corrin’s giggle. “Ah, it always surprises me how big you are.” Xander just chuckled a little at that as he urged Corrin to wrap her legs around his waist. That was something Leo didn’t need to know. He didn’t need to know how much bigger his brother was then him. Leo knew he wasn’t the biggest guy in the world. He was always being compared to his brother though, or maybe he was always the one doing the comparing. The younger prince didn’t need to know about another thing Xander bested him at. 

“Hm, I need you to relax Corrin.” Xander grunted. Leo could see it in his head. Corrin with her thick thighs wrapped around Xander's strong body, her black panties just pushed to the side while his brothers pants were down just far enough to free his apparently impressive cock. Leo wished he could imagine it was him in Xanders place, but his mind wasn’t co-operating right now.

Why was he still stroking himself? Why? The thought of his sister trying to relax to take in Xander, the sounds of her and Xanders soft gasps as he tried to pushed in. Leo knew the exact moment when Corrin took Xanders dick inside of her. The loud low moan from her and the grunt from him made that oh so clear. Leo’s hand moved faster on his own cock. Gods he was so filthy to be getting off to this. 

Soon the sounds of the two of them making love could be heard. Leo didn’t dare call it fucking, the soft whispers of adoration between harsh breaths made it very clear to him how they felt for one another. The creaking of the shelves in time with Xander's thrusts, as well as Corrin’s gasps of pleasure and begging for more made it oh so easy to match their pace with his hand. Leo sat, back against the bookshelf they were having sex against, tears streaming down his face as he jerked himself off to the sounds of two very much in love siblings make love. Each time Corrin begged for her lover to take her harder, or told him how good he was, sent daggers into the young blondes heart. It was a blessing to that Xander wasn’t loud at all, though his quiet praises of how perfect she was seemed to mirror his own thoughts of her.

What was supposed to turn out to be a quick session between the two seemed anything but. Time seemed so slow, as any glimmer of hope to somehow convince Corrin to fall for him was blown further and further away. Every gasp that spilled from her lips both excited him and crushed him at the same time. Instead of his name spilling from her lips it was Xanders. The two of them had settled into a pace it seemed and she could barely get the name out. It was like a chant though, Leo wasn’t even sure she knew what she was saying at this point. Gods, he could hear it, each thrust Xander made into her sopping wet cunt he could hear. 

It was to those sounds and the image of his brother blowing the love of his life that made Leo cum. He finished before the two of them, which was another blow to his already bruised ego. He didn’t even have the stamina to keep up or make Corrin cum. Wiping his hand on his cum and tear stained pants he sat there for a second recovering. Finally he got up on legs as shaky as a newborn foal and quietly left the library. Not before he heard Corrin’s frantic cry as she presumably came on his brothers cock. Leo winced, he had been hoping to make it out of there before having to listen to that. Luck it seemed was just not with him that day. Sighing Leo just hoped he didn’t run into anyone on his way to his room. He wasn’t sure how he would explain away the stain on his pants or his red and puffy eyes. All he wanted to do was go his room, curl up in a ball, and go to sleep. Maybe this was all some sort of horrible nightmare.

**Author's Note:**

> Let me know what you think. Also, any comments on what to improve or what I missed are always appreciated. 
> 
> Also, I guess I take fills if people want them. It just takes me a few months to get around to writing them.


End file.
